Gene driven insects

April 2016

Not content with Nature's measured pace for adjusting the genome to suit the ecosystem, the environment and the future, genetic engineers have devised a way to force GMOs to add an extra copy of artificial DNA into their offspring.  This creates a mutagenic chain reaction which drives the artificial DNA progressively into subsequent generations.

The 'gene-drive' is based on a bacterial genome-editing technique described by GM-free Scotland before - CRISPR-Cas9 [1].  'Cas9' is an enzyme which cuts DNA, while the 'CRISPR' part is a homing device to anchor the Cas9 to the desired bit of the genome.  In a gene-drive, the CRISPR-Cas9 stays where it is in the genome and carries on mutating the genome of the wild-type mate during reproduction to produce nothing but mutated offspring.

This means that what genetic engineers can do now is population engineering, and if applied to wild populations this is ecological engineering.

Self-copying genes rampaging through a population seem to many (even scientists) akin to a highly virulent molecular plague.  Indeed, lots of clever technical tricks have been proposed to control gene-drive organisms once released: for example, installing a need for two interacting drives; or drives which are switched on or off by the presence of a chemical.  As a last resort, another wave of GM organisms could be released with gene-drives to cut out the one causing the problem in the first place.

Like all GM techniques, CRISPR-Cas9 will have unpredictable effects on the functioning and evolution of the genome.

COMMENT.  The engineered genome will also have unpredictable effects on the functioning and evolution of the species, and the engineered population will have unpredictable effects on the functioning and evolution of the ecosystem (and that includes humans).  With a "near certainty of spread across political borders" (Esvelt), there will also be unpredictable effects on international relations.  Marvelous.

Gene drives are only useful, of course, if the organism to be changed breeds very rapidly, and one of the easiest things to achieve with genetic engineering is annihilation.  Suitable candidates, therefore, include many pests, diseases, and invasive species (especially those threatening to wipe out endangered species). 

Also, since the technique is readily available to "any malign individual or organisation with access to modern laboratory equipment", the scope for the manufacture of self-driving biological weapons is limitless.

So far, attention has centred on reversing the resistance to weedkillers and insecticides created by GM crops in the first place.  In other words, gene-drives are a neat means to perpetuate business-as-usual for the biotech industry.

High-profile in the media has been the most likely first target for gene-drive technology: wiping out disease-carrying mosquitoes or rendering them unable to transmit the pathogen [2].

OUR COMMENT

There won't be any such thing as a natural or artificial 'refuge' in which non-gene-driven organisms can survive and dilute out emerging mutants: catastrophic destabilisation of ecosystems is a real possibility. 

Worse, the danger that the artificial DNA is unstable or causes instabilities elsewhere in the genome is very real: whatever it mutates into will then be driven through future generations.  The vision, as presented by one Nature Magazine senior reporter, is of wild GM populations accumulating gene-driven mutations in their artificial DNA from generation to generation.  Rather than controlling pests and pathogens, the GM cure could prove worse than the disease.

Gene drive technology shouldn't be released into the environment for the same reason that man-made radio-active materials in any form shouldn't be there either.

Don't sit back and let nasty gene-driven surprises creep up on you.

Background:

[1]  CRISPR/Cas9 GENE EDITING - March 2016

[2]  ZIKA AND SUPER-ZIKA - April 2016

SOURCES

• Kevin Esvelt, et al., 2014, concerning RNA-guided gene drives for the alteration of wild populations, eLifesciences.org
• James E. DiCarlo, RNA-guided gene drives can efficiently bias inheritance in wild yeast, Cold Springs Laboratory, 16.01.15
• Outsmarting Nature​: Synthetic Biology and "Climate Smart" Agriculture, Heinrich Böll Foundation, November 2015
• Dr. Mae-Wan Ho, CRISPR Too Fast for Comfort, Institute of Science in Society Report 12.01.16
• Driving test, Nature 524 6.08.15
• Heidi Ledford, Caution urged over DNA editing in wild, Nature 524 6.08.15
• Omar S. Akbari, et al., Safeguarding gene drive experiments in the laboratory, Science Magazine, 30.07.15
• Steve Connor, 'Gene drive' Scientists sound alarm over supercharged GM organisms which could spread in the wild and cause environmental disasters, Independent 2.08.15
• Sharon Begley, Gene drive gives scientists power to hijack evolution, STAT 17.1115